Hi ,
      I am getting An item with the same key has already been added. error . Here is my code.

    <DockPanel x:Name="LayoutRoot">
        <Grid>
            <igCA:XamChart HorizontalAlignment="Left"  Name="XamChart1" VerticalAlignment="Top"  >
                <igCA:XamChart.Axes>
                    <igCA:Axis AxisType="PrimaryX">
                        <igCA:Axis.Label>
                            <igCA:Label Format="{}{0:MMM-yyyy}" FontWeight="Bold"/>
                        </igCA:Axis.Label>
                    </igCA:Axis>
                    <igCA:Axis AxisType="PrimaryY">
                        <igCA:Axis.Label>
                            <igCA:Label Format="{} {0:C}" FontWeight="Bold"/>
                        </igCA:Axis.Label>
                    </igCA:Axis>
                </igCA:XamChart.Axes>
            </igCA:XamChart>
        </Grid>
    </DockPanel>

  Using context = New MVEntities()
            Dim query = context.GetChartData(13).ToList
            Dim seriesUnitsInStock As New Series()
            seriesUnitsInStock.DataSource = query
            seriesUnitsInStock.DataMapping = "Value = Amt; Label = MonYr; ToolTip=Amt"
            Me.XamChart1.Series.Add(seriesUnitsInStock)
        End Using

query has two columns MonYr (1st day of the Month) & Amount.

Any idea how to resolve the error?

Thank you